In a virtuoso prime-time performance against one of the NFL’s nastiest defenses Monday, Colin Kaepernick created a sensational stat line and, possibly, a quarterback controversy in leading the 49ers to a 32-7 drubbing of the Bears at Candlestick Park.

Subbing for Smith, who sustained a concussion on Nov. 11 and was officially ruled out of the game Monday morning, Kaepernick completed 16 of 23 passes for 243 yards and two touchdowns in his first NFL start.

A second-round pick in the 2011 draft, Kaepernick, who posted a 133.1 rating, left little doubt he’s ready to be a NFL starter. The question: Will he start Sunday in New Orleans?

Smith, after all, led the 49ers to a 6-2-1 record, leads the NFL in completion percentage (70.0), ranks third in passer rating (104.1) and has completed 26 of his past 28 passes.

In other words, he’s pretty good.

With Kaepernick at the controls Monday, however, the 49ers’ offense bordered on great in a first half that concluded with them owning a 20-0 lead.

Against a defense that swaggered in allowing 14.8 points and 307.3 yards a game, San Francisco had 20 points and 232 yards … in the game’s first 23-plus minutes. The Bears also arrived with a NFL-high 30 takeaways, but they didn’t force a turnover against an offense led by a wet-behind-the-ears signal-caller.

With Chicago likely expecting the 49ers to formulate a cautious game plan for a 25-year-old with 31 career attempts, Kaepernick completed an eight-yard pass to wide receiver Mario Manningham on the game’s first offensive play. Two plays later, he threw a 22-yarder to tight end Vernon Davis.

It was harbinger of darts to come.

In his first two series, he completed 7 of 8 passes for 114 yards and floated a three-yard touchdown to Davis to give the 49ers a 10-0 lead. His game-opening sequence included a 57-yard, over-the-shoulder completion to Kyle Williams he flicked 41 yards in the air.

Even the Howitzer-armed Kapernick’s rare first-half incompletions (there were three of those in 15 attempts) were impressive.

On San Francisco’s third drive, he threw a quick slant that bounced off Randy Moss’ hands. Moss then briefly left the game. The diagnosis: finger injury.

Most impressive? Kaepernick was primarily a pocket passer Monday after he was often hasty to leave the pocket in his 8-carry, 66-yard relief appearance Nov. 11 against St. Louis. The only quarterback in NCAA history with three straight 1,000-yard rushing seasons, Kaepernick had three carries for 11 yards.

Kaepernick’s starring starting debut stole some of the spotlight from a smothering defense headlined by outside linebacker Aldon Smith, who had five sacks, the second-most in franchise history. Smith, who leads the NFL with 14.5 sacks, has 28.5 career sacks, the third-most in NFL history for players in their first two seasons.

The Bears’ game-opening drives ended with five punts and an interception. Chicago did not cross midfield until midway through the third quarter and finished with 151 yards, their fewest since Oct. 3, 2010.